Property maintenance tasks are commonly performed using various tools and/or machines that are configured for the performance of corresponding specific tasks. Certain tasks, like cutting trees, trimming vegetation, blowing debris and the like, are typically performed by hand-held tools or power equipment. The hand-held power equipment may often be powered by gas or electric motors. Until the advent of battery powered electric tools, gas powered motors were often preferred by operators that desired, or required, a great deal of mobility. Accordingly, many walk-behind or ride-on outdoor power equipment devices, such as lawn mowers, are often powered by gas motors because they are typically required to operate over a relatively large range. However, as battery technology continues to improve, the robustness of battery powered equipment has also improved and such devices have increased in popularity.
The batteries employed in hand-held power equipment may, in some cases, be removable and/or rechargeable assemblies of a plurality of smaller cells that are arranged together in series and/or parallel arrangements in order to achieve desired output characteristics. However, when these cells are arranged together to form battery packs, it is important to consider that different cells may have different characteristics that could impact interactions between the cells. For example, if one cell begins to deteriorate or fail, it may reach full charge before other cells and then be exposed to high temperature and/or pressure stresses while other cells continue to charge. Furthermore, if one cell in a parallel group of cells fails (e.g., short circuits), other cells may begin to discharge at a high rate through the failed cell, which may again cause large thermal and/or pressure stresses that could result in damage to the battery pack.
To avoid damage to battery packs, it may be important to consider employing design features that can either prevent or reduce the likelihood of the early onset of failure for one cell or a group of cells, or otherwise provide safety mechanisms to mitigate or prevent damage when such a failure occurs.